Curing bag



Feb. 3, 1948. T. E. THOMAS Y ,2,435466,

wams BAG Filed July 30, 1945 2 srlees-sheet 1 INV ATTORNEYS ENroRTALBOTT E..THOMA5 Feb, 3, 194s. T, E, THOMAS Y 2,435,465

CURING BAG Filed July 30, 1945 2 Sheets-Sheet 2 lar/11111111114 'lll,llfeclzqlll(l!lnlllllllb TALo E THOMAS ATTQRNEYS BY 'f V Patented Feb.3, 1948 CURING BAG Talbott E. Thomas, Cuyahoga Falls, Ohio, assignor toThe Firestone Tire & Rubber Company, Akron, Ohio, a corporation of OhioApplication July 30, 1945, Serial No. 607,714

s claims. 1

This invention relates .to valved iniiatable curing bags and refersparticularly to air, inert gasses, water and steam bags for .use incuring or vulcanizing pneumatic tires `and to method of producing same.

In vulcanizing pneumatic tires, iniiatable formers, commonly `referredtoas curingbags, are generally used in providing the required internalpressure to force the tire against the tire mold. Such curing bags are-expansible .endless tubes composed of rubber, yor rubber like material,and are provided with metal `inflation valve stems to facilitate theintroduction of air, water `or other suitable uid under pressure. Thevalve. stems are secured tothe inner .or baseY walls of `the cur.- ingbags, extending through .Saidwalls and have means for attachmentthereto,` but considerable difficulty has been experienced in eiecting aHuid-tight anchorage of .the -stem in 4or on the rubber which willVcontinue to b e -fluid ltight through successive tire curing operations.In service, after a curing bag has .been used in a tire curingoperation, thebag is removedfrom the cured tire and used in the curingvof another tire and in like manner for as -many additional tire curesas the condition of the curing bag will -permit. Since'curing .bags areexpensive `and since a leaking bag may cause a vdefective tire, itisidesirable to `get theV maximum number of cures from each bag and -toovercome the v`causes of bag failures.- One `of, the most common causesof failures of curing bags is leakage of the ination uid along and pastthe valve stem. This type of bag failure is knownas a valve leak. Twomethods 4of vcombating, curing bag valve leaks have been resorted to inthe art. One method depends upon obtaining 4a bond between the rubberand the. metal curingbag stem, and the other method to mechanicallydrawing the base of a valve stem against the inside wall of thebaseportion of the b ag thus obtaining .a ,fluid tight seal. Inserting orremoving a .curing bag from a tire results in extreme distortion of theArubber in the bag walls; however, the metal valve stems are notdistorted, which results in the rubber prematurely breakingv itsadhesionor bond to the metal, or in the case of a mechanical valve stemin the rubber pulling from between clamping members. When a valve leakoccurs it may develop during the tire curing operation in whichv eventitis often necessary .to classify the tre as defective. yA valve leak ina curing =bag in which rubber adhesion to the valve stem is employed toprevent. leaks usually results in scrapping the bag or at least inbuilding into the bag anew valve ,stem to replace the old. VBuilding innew stems is expensive and not entirely satisfactory since vbags withreplacement or built-in stems often fail before many additional cureshave been obtained. Even so, curing bag constructions in which anadhesion 4between the rubber and metal valve stems was depended on toprevent leaks portions. and in large .sizes often two .inches or,

more thick. The rubber compound or similar material of which `curingbags are composed .cannot long resist the pressure necessary to ndrawthe valve base against the inside portion of the bag wall base andconsequently ,gradually ilows from between the pressure members, namely,the valve stem base ,and external washer. Such movement of .stock awayfrom the pressure members Yoften resulted in valve leaks.

An object of the present invention is to provide .a valve stem forcuring bagsandtire inner tubes, said stem .having ,clamping membersmechanically movable toward each other on the valve stem, the clampsbeing so shaped as to prevent rubber or the material composing the basewallfofthe bags .or tubes from escaping `from between the clampingmembers.

Another object of the invention is to provide a hollow inflatablearticlehaving a valve stem which will be effective in preventing valve leakswhen used in such articles made of butyl rubber, or other rubber likematerials having poor adhesivequalities compared tonatural rubbercompounds.

A' further. object of the invention is to provide a curing bag valvewhich providesv means for trapping the material of which the bag iscomposed, between clamping members and the valve stem proper, andyforcing the trapped material firmly about the valve stem when saidclamping members are moved toward each other.

.A still further object of the invention is to provide convenient meansfor operating valve stem clamping members vexternally 4of a bagthroughout a bags life.

Another object of the invention is to provide a valve stem for curingbags which stem may,

ent from the following description in connection Y with the accompanyingdrawings,rwherein a prefv I ferred form of the invention has been shownby way of illustration, and wherein:

Fig. 1 is a perspective view of an end portion of a curing bag, showinga valve embodying the present invention in position in the bag beforethe bag is vulcanized in a curingv bag mold;

respectively. I'he bores 29 and 2I terminate at their inner ends in anannular shoulder I9. The sides of the bores and 2l are threaded withright hand threads 22 and 23 respectively. It is to be noted, however,that the side of the bore 29 for a distance from its outer end is smoothand is radially outwardly tapered. Side 21 of the cupy 26 has anchoringnotchesvor grooves 28 formed in its edge and air vents 29 provide meansof escape for air which mayY become trapped in the cup. Y.

The cup member I 5 has a, centrally disposed axially outwardly extendingportion 30 havingv external pipe threads 3|. Member I5 has a left handthreaded bore 8 extending Vaxially through the center of said members I5and 30. The sideV 'l 33 of the cup portion 32 of member I5 has notchesFig. 2 is a fragmentary sectional view showing relative positions of thevalve parts and the curing bag as they appear preparatory kto tighteningclamping members against the base wall of the curing bag, one ofthevalve parts being a hollow bolt show partially broken away showing avalve socket lin the end thereof Fig.3 shows in elevation a suitablewrench for tightening the clamping members of a valve stem embodying thepresent invention;

Fig.4 is a sectional view showing the valve tightened in positionpreparatoryto laying the bag in its vulcanizing mold with a valveextension and washer in place as in Fig. 1;

. Fig.V .5 is a plan view taken on line 5-5 of Fig. 2;

Fig. 6 is a View taken on line 6--6 of Fig. 2;

Fig. 7 is a longitudinal section view through the valve portionk of anished bag showing a flexible hose connected to the inner end vof thevalve;

Fig. 8 is a transverse sectional View on the line 8-8 of Fig. '1; and

Fig. 9 is a fragmentary sectional view modified form of the invention.

The invention has been illustrated in the drawings as applied to acuring bag, which may be formed of butyl or natural rubber compound orofa of any other suitable material, and which is in the form of apliable annular tube I8 the interior of which constitutes a uid chamberI I into which air, inert gas, steam, water or the like may beintroducedthrough a Valve stem indicated generally at I 2. The bag I9 is of such across sectional configuration when iniiated as to conform to the sizeand shape of the interior of a nished tire. In service the bag ismounted in an unvulcanized tire to provide the internal tire pressurenecessary for proper molding and vulcanizing of the tire. It has beenfound advisable and itis common practice in most sizes of bags to formthe inner wall or base I3 of the bag thicker than the other wallportions for reasons well known to those familiar with the art.

By reference to the'drawings, it will be seen that the valve stem I2comprises an outer cupshaped anchorinember I4 whichV is formed ofbrass.' an inner cup-shaped anchor member 15g also formed of brass, anda corrosive resistant metal hollow bolt or externally threaded tube 9composed of stainless steel or the like and a valve extension 5I).`

or grooves 34 cut therein, and has air .vents 35 traversing the side 33from the bottom portion' of the cup to the bottom of the notch 34. Thebore 8 terminates at the bottom of the cup portion 32 in an unthreadedared wall 1. Only four notches 2 8 and 34 and two vents 29 and 35 havebeen illustrated but it is to be understood that the invention is notyto be limited to a particular number of notches or vents. Y

The anchor members I4 and I5 are in spaced relation and are carried inthreaded relation with the hollow bolt 9, said bolt havingvoppositelyexternally threaded ends 35 and 31. The end 36 has a left and end 31 hasa right hand thread. The bore through the bolt 9 is round except at theouter end of the bolt's end portion 31 the bore is broached and isadapted toy receive in operative relation a complementary shaped endpor-l tion 38 of a wrench 39 .the wrench having cross handle 5. Thethreads on the 'bolt extend from the outer ends of the bolt to themiddle area leavingV an unthreaded portion 40 of 1A" or more in width,said portion 40 being cut into the bolt approximately as deep as thethreads. l The end 31 of the bolt terminates in a cone shape portion 6which portion seats against a seat 42 on the l Vshoulder I9 vwhen thecups or clamping members VThecup -member I4 has extending from its.`

cupped portion 26 a centrally positioned cylin- 'g drical-boss I 8 andan axially outwardly projecting portion 24 extending from the centralportion of the base ofthe member I4, said portion 24 being Icylindricalwith flat side portions 25. The boss I8 'and projection 24have axial bores 20 and 2l I 4 and I5 have been drawn to their extremeclosed position. Y.

A valve stem extension 50 having threaded portions 6 I and62 andterminating at its ends in cone shape portions 5I and 52 are provided.The portion 52 of said extension is adapted to'seat on a seat 53 on theannular shoulder I9. The portion 5I is adapted to seat in a properfitting, not shown, connected with a source of fluid pressure such asair, steam, water, inert gas or other pressure medium which may be foundto be satisfactory.

Preferably a rigid washer 58 backed up by a hexagonal nut 59 is used inthe manner common Yin the art. eo A dium a drainage hose 54 is attachedto member I 5by means of a cap 55V retained in threaded relation on thethreads 3| of the portion 30. The opening inthe hose 54 vcommunicateswith the .inside 56 of the cap 55 through a threaded opening 51 intowhich it is threaded. y Y

. In the manufacture of a nished curing bag the components I4- I5, 9,58, 54, 55, 58 and 59 of the I2 are manufacturedseparately by meth- .odswell known to those familiar with the art.

While the hollow bolt 9 has been shown as hav- Y`ing a round'centralhole except at its broached .end, it is to beV understood that theinvention is not tobe limited to such a Vbolt since hollow bolts withsquare holes running its entire length would A-rriandracture 1 oficuring bags.

' bea convenient wayof `manuf actu'ring-i al liolltv bolt and a wrenchwith afsquare en'd -a'daptedto Other methods of turning the bolt,such,'for exnample,- as by'the use ofa keyed wrench,l fw`ill`occur -1"tothose having mechanical skill; therefore it is' to 'fbe understood'that such-modicationsare-within "thespirito'f the invention. 'Ihe bagIfislc'oin- -posed idf butyl rbberand is formed by zan `'exrtriid-ing ortube' machine operationcommon inthe ``4After 'the uni/fuln canzedextruded `bag has been cut to'length,ior

#approximate 1ength,fa valve hole SI1-is punched throughthe'fbagf atitslbasewall I3. The members' 9, I5,I54 and -155 fare assembled? bystarting thebolt'- n'itslthreade'drelation with the memberintolpositionfrelative'to portion v/30 of theln'ernber l life-ndr'attach-ing thehose `-54 in Y tnreadedr Irelation withthe cap 54. lThisassemblyis then placed inside'thefunvulcanized bag withthe end31 of ithe '-boltlproject'ed throughthe Valve `hole/'60 land with theedge ofthe cup 32c`ontacting' the inside surface of the'bag I0.Next1thefembossed-portion 20 of memberv I4 is pressed 'into valve holeBI) until the threadedp'ortion .131 ofbolt '9"-conta'ctsthe threads22#of the' boss I8. Thellength of thebolt 'islv suchl relative `itcbthethickness of i the f base I 3 that said-"contact is made just beforethe` edge of theiside''l' ofthe cup 251eontacts the outside sur- 'faceof said' base I3. vByusingfasuitable wrench onf the ilats 25 ofi theprojectingzportion '24 the tmember' I'4 isr'un down'on the threadsfofthe fbolt until the edge of the'sidefZl-contacts the suface of thebag. :It is/toibe noted that in this'postion thatzthefedges of the cupsof 'membersV I4 and I5 are-in threaded relation with the bolt and inopposed relation in contact with opposite sides of the base of the bag.Next the Lend Y38 4of the vwrenchf-SS is insertedinthe end-f31 of thebolt and the bolt is" turned counter-clockwise. As will Vbe-seen-'byreferenceto the leftrandlright hand threaded -arrangement of the' boltanclmember I4 and I5 the counter-clockwise turning of the bolt draws theclamping membersfM and I5'toward each other with themechanicaladvantageof both l the wrench and the threads. The clampingmembersare drawn toward reach. other-until the sides '21.andi33 ofthemembers, I4 andISreSpectively vcut into the base -I3 far "enough topermit lthe bottoms of the cupsof said members I4 and I5 to lcontactvthe baseV I3, or, in'other'words, until said cups areiilledwithbutyl/rubber or other material -of which-the bag may becomposed. Thedrawing of Vthe members I4 and I5 against? the unvul- Ycanized rubber causes a pronounced depression in the'base ofthebag-aboutfmember I4 with the portion/24 projecting outwardly throughthe depression. Next the valve extension 50 is threaded .into .positionin portion 24 with titsv 'ooneshape .'porti'on5l of the 'extension 50seated inl fluid'tight relation on its'seat 52. AV washer url plate58'is .l placed on thev extension-5I!v and is backed up with ra lock nut59 rundown onlthrea'ded portion 6I of =said extension thus'anchoringthewasher against the fend ofthe-boss 24and.locking theextension'against-its seat 52. The-"bag .is next spliced-in the usualmanneran'd` laid in a curing `or v-ulcanizing mold with the bagconnected to a continuous supply of air, or steam pressure or the like,through the'extensionvSlJ. kAsthe internal Ipressure builds up in ,thebag the rubber is v.pressed vagainst`= the sides `of the bagim'old` andSas fthe bag material becomesheated Vftherubber,or

other'suitable materiall fof which Vthe bag may be VContact with thevalve.

fco'mpesed, molds -or i-flows-ab'out the washer "58 leavin'g 'the fcupALpo'rtion A26ff member I4 vcompletely embedded in the basefoflthebagvas will "be seenb'y referencetovFigsjl, 7andl'8. In drawing-thercup'fmem'bers I 4 fand I5 into clamped relation fwith the bag-baseescape of air from the cup is prevented l by Contact 'of the rubber withthe edges of the'cup members. It is desirable that trapped'air--inthe'c'upsV be' avoided andmeans for perniittingthe escape oflair -fromthe bottom of thefcup-members I4l'and` I5 are provided byvents 29 andf35respectivehr. After the'rubber enter- I ing lthe cup'sforces theairfrom the cups through Athe'ventstherubberlfollows the air and iills thelvents withrubber. l'Ithas been found that if the Vdiameter ofthe-vents' does not'exceed 32" Aof an 1 inchthat therubber'moldedtherein prevents air or `other internalcuring pressure medium `frompassingfthrough the'vents'even though the outer ends ofthe vents becomeexposed to the internal pressureniedium.

The `bag I0 has been illustrated as `being equipped with one 'valveonly; however, if two valves are to be'used, as is sometimes .the casevwhen circulating h'ot water is used as an internal pressure and heatingmediunntthenV-an additional valve I2 may be installed in the samemanner/describedabove. If airis to be used as the internal pressuremedium the drainage hose'54 may be omitted and a modified Vcap besubstitutedforicap `55. Such modified cap-maybe similar vto cap 55 buthaving a plurality 'of holes 'suchas hole 51 Vexceptthe holes need'notbe threaded and the hose 54'mayrbe omitted.

`VAAfter the curing bagrhas been removedifrom itsI curing mold theextension 5e is removed'an'd clamping members'M and I5 drawn toward eachother'by means of the wrench`V 39 inserted infthe hollow bolt I2. It hasbeen found that about one turn of said bolt is'sucient for this initialtightening-of theclamping members after'the bag has 'been'moldedfDuring'the' cure of the bag the rubber is forced against vthe saidbolt, clamping members land washer sothat uninterrupted contact is madetherewithfhowever, it has been found that the tightening of the clampingmembersasjustfdescribed presses the rubber more iirmlyintothe cupportions and about the metal between the "cup portions. AIt isparticularly pointed out that as the cup portions move toward each otherthat the rubber is severely .crowded between the'bolt and the inclinedplane surface of the Aradially outwardly flared unthreaded portionsfofthe clamp members I4 and The small volume 'of rubber compressed withinsaid'ared .portion forms high compression ribbon-like collarsofrubberwhich are rVery Aefectivein preventing fair, steamior water orother inflation pressurelmedium from leaking betweensaidhi'ghly'compressed rubber and the metal. Whether the explanationoi?Y how the rubber in saidiflaredpo'rtions prevents leaks is accurate,it'has beenfou'ndthat when the ared yfeature is embodied in the -valveconstruction,

= from .f the? pull .zand i crowd :f fthe rubber during `were used. Thegreater the distance required for a leak to develop on a long valvestem, the more tires can be cured before a valve leak occurs;

however, in the present valve constructionV not Y only is the distancefrom the inside of the bag along the surface of the valve stem to theatmosphere increased over that of `any previous valve stemk constructionof which applicant has any knowledge, but the greater distance includesareas in the cups where the rubber is protected against distortion andareas along the metal where the rubber has been subjected to mechanicalpressure over the normalpressure received during the vulcanizing andmolding of the curing bag. Heretofore the rubber adjacent the valvestems of curing bags have been subjected to mechanical pressure, therubber being squeezed between a valve stem base in contactY with theinside surface of the bag and a Washer against the outer surface 'of thebag; however, as is well known, rubber under pressure gradually flowsaway from pressure, and this is particularly true when the rubber issubjected to high temperatures as it is in vulcanizing tires. Applicantscups trap the rubber therein and eifectively combat the movement of therubber away from the mechanical pressure area created by the clampingmembers. In order to further resist the flow of rubber away from thevalve stem and to force the rubber firmly against the metal and boltwithin the cups the cup portion 26 has a smaller diameter than thediameter of cup portion 32; thus as these cups approach each other theinner cup tends to overlap the outer cup and it has been found that thisarrangement is more eifective in preventing valve leaks than opposedcups of the same diameter. Y

The notches 28 andY 3.4 in clamping members i4 and I5 respectively serveto anchor the cup portions 23 and 34 against turning when the bolt 9 isturned by means of the wrench 39 for the purpose of drawing the clampingmembers toward each other.

Although the present valve construction has resulted in an increase inthe number of tire cures on a curing bag before a valve leak developssuch leaks may develop if the bag does not fail from other causes. Whena valve leak does develop in a, bag using the present valve` stem theleak can be stopped by the simple expedientk of removing the extension50 thereby exposing the broached portion of the hollow bolt 9, insertingthe end 33 of the wrench 39, manually turning the wrench causing theclamping members I4 and I5 to travel axially toward eachother onV thethreads of the bolt 9. After the clamping members have been drawn towardeach other a distance sufficient to again seat the rubber about themetal of the valve stem in air tight relation the extension 50 is againthreaded into operative position and the curing bag is ready for serviceagain. the clamping members come into contact; however, it has beenfound that curing bags usually fail from some other cause before thepresent valve stem reaches its limit of clamping movement. After acuring bag in which-the present This operation may be repeated untily Y8 valve' stem has been used fails the valve stemls simply removedfromtheold bag and-transferred to a new bag `by .disassembling and reassemblingits parts. Y

The modified form of the invention illustrated in Fig. 9 shows a valvestem 'Ill with itscomponents and a fragment of a curing bag in therelative positions to each other they occupy preparatory to tighteningclamping members of the valve stem against the base wall of the bag.Valve stem 'Ill comprises outer and inner :cupshaped anchor or clampingmembers 'II and 'I2y respectively, and two hollow bolts or tubes 'I3 and14. Clamping member II hasy extending from the bottom of its cuppedportion aV cylindrical boss 16. A smooth central axial bore 'Il passesthrough member 'Il and boss 16.

Anchor or clamping member 'I2 has a centrally disposed axially outwardlyextending portion V'I8 having `external pipe threads 19. Member 'I2 hasa central axial smooth bore 8mo extending therethrough whichcommunicates with a similar, but

somewhat larger bore 8l formed through the portion 'I8 of member '12. Ashoulder 82 is formed 'at the junction of bores 89 and 8I. Hollow bolt'I3 has an annular radially outwardly extending shoulder 83y adapted tobear and turn against'the outer flat surface about the bore l1 of member1I. The inner end of bolt 73 has internal threads Sil-and a seat 85opposite the shoulder 83, said bolt`l3 having anV axially outwardlyprojecting portion 86 which portion hasan axial bore 8l. The side ofbore 81 has threads 88 to receive in threaded relation a curing bagextension not shown, in similar manner as extension Ellis received inprojection 24 as was explained hereinabove in reference to Fig.'4. i

Hollow bolt 'I4 has a head 89, and external threads 93, said threads 99lbeing adapted to engage threads S4 of bolt '13. The bore of the boltV'lll is broached providing a socket for a Vwrench by which bolt 'I4 visturned wherebythe cup-shaped anchor or clamping membersY 1I and l2 aredrawn toward each other.

In assembling'valve ,'13 ein' operative position in the pliable annulartube or bag I 0a valve stem hole Si) is punched through the base of thebag. Next the hollow vbolt I4 is projected into member 'l2 with theheadr89 against shoulder v82. Before-the curing bag is spliced thisassembly of members 'I2 and 'I4 is inserted in the open-end Vof the bagand the bolt 'I4 is projected into the hole 60 until the cup member 'I2contacts the inside of the bag I3 and the bolt head 89 contacts theshoulder '82.

member 7l. Y. The bolt 'I3 is projected into hole 6l) until its threadend contacts the threaded portion of bolt T4. Next a wrench similar towrench 39 but of suitable size is inserted through the boreV of bolt 'I3into the breached lportion of bolt I4 which forms a wrench socket. Nextthe bolt 'I4 is', turned on its axis and as the said bolts are inthreaded engagement by turning bolt r'I4 the bolts may be tightened upand the shoulder of the cup members of Fig. 2 and serve the same Nextthe cup member 'II andV the bolt 'I3 are similarly assembled with the Yshoulder 83 in contact with the surface of cup 9 purpose. A cap such as55 of Fig. 7 may be attached in threaded relation to portion 18 anddrainage hose, such as 54 of Fig. '7, may be attached to the cap.Obviously Valve stem 10 functions in a manner very similar to valve stemI2 and for that reason a further discussion is deemed to be unnecessary.

While, throughout the specification, I have referred to a valve and avalve stem, it will be understood that these are shop terms used todesignate a hollow filling stem, and actually there is no valve includedin the stem.

It will now be apparent that an improved curing bag and novel method forproducing same have been provided constituting a substantial advance inthe art. While the invention has been disclosed as specifically embodiedin a curing bag, it is not to be restricted to such use since thesalient features may be incorporated in other types of inatablearticles.

Furthermore it is to be understood that the invention is susceptible ofmodifications in the details of construction and arrangement of parts,and the right is herein reserved to invoke such changes as fall withinthe scope of the appended claims without departing from the spirit ofthe invention.

What is claimed is:

1. An inatable article, comprising a hollow body of pliable material, avalve stem extending through the wall of said body, said valve stemconsisting of a hollow bolt threaded with opposite threads at each end,a pair of cup-shaped anchor members mounted on said bolt, saidcup-shaped members having axial threaded bores therethrough and beingmounted on said bolt in threaded relation therewith with the concavedsides of the cup-shaped members in opposed relation.

2. An inflatable article, comprising a hollow body of pliable material,a valve stem extending through the wall of said body, said valve stemconsisting of a hollow bolt threaded with OPPO- site threads at eachend, a pair of cup-shaped anchor members mounted on said bolt, saidcupshaped members having axial threaded bores therethrough and beingmounted on said bolt in threaded relation therewith with the concavedsides of the cup-shaped members in opposed relation, said bolt beingaccessible externally of said body and being turnable on itslongitudinal axis in the wall of said body by means of a wrench insertedin its externally accessible end.

3. An iniiatable article, comprising a hollow body of pliable material,a valve stem extending through the wall of said body, said valve stemconsisting of a hollow bolt threaded with opposite threads at each end,a pair of cup-shaped anchor members mounted on said bolt, saidcup-shaped members having axial threaded bores therethrough and beingmounted on said bolt in threaded relation therewith with the concavedsides of the cup-shaped members in opposed relation, the cup portionproper of the outer of said cup-shaped members being entirely embeddedWithin the base portion of said inatable article.

4. An inflatable article, comprising a hollow body of pliable material,a valve stem extending through the wall of said body, said valve stemconsisting of a hollow bolt threaded with opposite threads at each end,a pair of cup-shaped anchor members mounted on said bolt, said cupshaped-members having axial threaded bores therethrough and being mounted onsaid bolt in threaded relation therewith with the concaved sides of thecup-shaped members in opposed relation, said axial bores terminatingadjacent the inside bottom of the 'cup portions in radially outwardlytapered smooth portions forming in cross section wedge-shaped spacesbetween said bolt and said tapered portions.

5. A valve stem for an inflatable article provided with a hollow screwthreaded bolt having a pair of cup-shaped anchor members in adjustablethreaded relation with said bolt, means for turning said bolt on itsaxis, one end of said bolt having a right hand and the other end a lefthand thread, whereby each of said anchor members are simultaneouslymovable toward the other by the turning of said bolt on its axis.

6. An inflatable article, comprising a hollow body of pliable material,a valve stem extending through the` wall of said body, said valve stemconsisting of a hollow bolt threaded with opposite threads at each end,a pair of cup-shaped anchor members mounted on said bolt, said cupshapedmembers having central axial threaded bores therethrough and beingmounted on said bolt in threaded relation therewith with the concavedsides of the cup-shaped members in opposed relation, the cup portion ofone of said cup-shaped members being entirely embedded within the basewall of said iniiatable article.

TALBOTT E. THOMAS.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,570,157 Knepper Jan. 19, 19261,927,803 Mullin Sept. 19, 1933 2,318,376 Crowley May 4, 1943 1,818,536Crossan et al Aug. 11, 1931 1,129,585 Newsom Feb, 23, 1915 1,419,471Reynolds June 13, 1922 1,485,526 Pulverman Mar. 4, 1924 FOREIGN PATENTSNumber Country Date 675,538 France Nov. 7, 1929 502,355 Germany Nov. 11,1928

